501
FXUS65 KBYZ 060516
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
1116 PM MDT SAT SEP 5 2026
KEY MESSAGES
- A WEATHER SYSTEM BRINGS THE CHANCE OF SHOWERS AND THUNDERSTORMS
TO THE AREA LATE SUNDAY INTO MONDAY. THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING HEAVY RAIN AND GUSTY WINDS. CANNOT RULE OUT
HAIL WITH DISCRETE THUNDERSTORMS ON SUNDAY AS WELL.
- WINDY CONDITIONS ARE EXPECTED MONDAY INTO TUESDAY (WIND GUSTS OF
25 TO 50 MPH, STRONGEST IN SOUTH-CENTRAL MT MONDAY AND EASTERN
MT TUESDAY). THIS WILL CAUSE ELEVATED FIRE WEATHER CONDITIONS.
- DRIER AND WARMER CONDITIONS ARE LIKELY DURING THE MIDDLE OF NEXT
WEEK AHEAD OF ANOTHER POTENTIAL WEATHER SYSTEM NEXT WEEKEND.
DISCUSSION
TODAY THROUGH SATURDAY...
AN UPPER LOW CONTINUES TO DIG THROUGH THE PACIFIC NORTHWEST
TODAY. LATER THIS AFTERNOON AND EVENING, AS THIS LOW MOVES
EASTWARD THE LEFT EXIT REGION OF THE TROUGH COULD BRING ISOLATED
TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT TO SOUTH AND
CENTRAL MONTANA. THE STORM PREDICTION CENTER HAS A MARGINAL RISK
(LEVEL 1 OUT OF 5) ACROSS MUCH OF MONTANA, FOR A FEW STRONG TO
SEVERE THUNDERSTORMS. THE PRIMARY CONCERNS ARE STRONG WIND GUSTS,
HEAVY RAINFALL, AND HAIL. CAPPING LOOKS TO BE A PROBLEM THOUGH,
WITH HIRES MODELS DEPICTING A STRONG ENOUGH CAP THAT HINDERS
CONVECTIVE DEVELOPMENT. THE EXCEPTION IS FAR SOUTHEAST MONTANA
WHERE A SURFACE LOW WILL EXIST AND PROVIDE A FORCING MECHANISM.
THE LOW CONTINUES MOVING THROUGH IDAHO THIS EVENING,
BRINGING A SHORTWAVE AHEAD OF IT. THIS WAVE WILL BRING AMPLE
FORCING AND A BETTER CHANCE OF PRECIPITATION (UP TO 70 PERCENT)
TO SOUTH- CENTRAL MONTANA INTO MONDAY. LOOK FOR SHOWERS AND WEAK
THUNDERSTORMS OVERNIGHT, BEFORE THE CHANCE FOR PRECIPITATION
GENERALLY COMES TO AN END THROUGH MONDAY MORNING. LINGERING
ACTIVITY MAY STILL EXIST OVER THE MOUNTAINS AND FOOTHILLS WEST OF
BILLINGS AS WELL AS ALONG THE DAKOTAS BORDER.
THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL MOVE NORTHEASTWARD
THROUGH MONTANA ON MONDAY. ISOLATED SHOWER AND THUNDERSTORM
ACTIVITY LOOKS TO ACCOMPANY THIS DURING THE DAY. THE THREAT FOR
STRONG TO SEVERE THUNDERSTORMS WILL BE VERY LOW. THE MAIN HAZARD
LOOKS TO BE THE SYNOPTIC WINDS ASSOCIATED WITH THE LOW PRESSURE
SYSTEM. AT THIS TIME, WIDESPREAD WIND GUSTS IN THE 20S TO 40S MPH
ARE FORECAST, STRONGEST OVER THE FOOTHILLS WEST OF BILLINGS. AREAS
AROUND LIVINGSTON TO BIG TIMBER AND HARLOWTON MAY EVEN SEE A FEW
50 MPH WIND GUSTS LATE MONDAY (50 TO 70 PERCENT CHANCE).
TUESDAY, WINDY CONDITIONS LOOK TO CONTINUE ACROSS MUCH OF THE
AREA, THOUGH THE STRONGEST WINDS WILL SHIFT TO BE OVER FAR EASTERN
MONTANA. AGAIN, WIND GUSTS IN THE 20S TO 40S MPH ARE FORECAST TO
BE COMMON, STRONGEST TO THE NORTH AND EAST, WITH A FEW 50 MPH WIND
GUSTS POSSIBLE AROUND BAKER, MONTANA (25 TO 40 PERCENT CHANCE).
WEDNESDAY INTO FRIDAY ARE FORECAST TO BE MOSTLY DRY DAYS AS LOW
AMPLITUDE RIDGING NUDGES INTO THE REGION ALOFT. BY LATE FRIDAY
INTO THE WEEKEND, THE CHANCE OF PRECIPITATION RETURNS, BUT
UNCERTAINTY REMAINS REGARDING THE UPPER LEVEL WEATHER PATTERN.
LA/PM
AVIATION
06Z TAF/AVIATION DISCUSSION...ELEVATED INSTABILITY WILL EXIST
ACROSS THE FORECAST AREA OVERNIGHT THROUGH TOMORROW. CAPE VALUES
ARE OVER 1000 J/KG FOR AREAS EAST OF BILLINGS AT 06Z WITH STEEP
MID LEVEL LAPSE RATES. THE LIMITING FACTOR FOR CONVECTION BECOMING
MORE WIDESPREAD OVERNIGHT INTO TOMORROW IS STABLE AND FAIRLY DRY
LOWER LEVELS (BELOW 8-10KFT AGL) AND A LACK OF STRONGER FORCING
MECHANISMS. THE RESULT IS LIKELY TO BE ISOLATED HIGH BASED
SHOWERS, MAYBE A TSTM OR TWO, SPONTANEOUSLY DEVELOPING OVER THE
EASTERN HALF OF THE FORECAST AREA THROUGH THE MORNING HOURS. BY
LATE MORNING MIXING OF DRIER AIR VERTICALLY WILL WORK TO DIMINISH
INSTABILITY PROFILES THROUGH THE AFTERNOON HOURS.
EXPECT ANY CONVECTION TO BE LIGHT BUT THERE IS REALLY NO FOCUS
FOR THIS ACTIVITY SO BE ALERT FOR DEVELOPMENT. FOG IS ALSO A
POSSIBILITY OVERNIGHT ALONG THE LOWER YELLOWSTONE AND TONGUE RIVER
VALLEYS (FORSYTH/MILES CITY) AND ALONG THE EASTERN STATE LINE
(BAKER/EKALAKA) FROM 09Z THROUGH 15Z. EXPECT LOCAL IFR OR LOWER
CONDITIONS WHERE FOG DOES MANAGE TO GET ESTABLISHED.
OUTSIDE OF THE ABOVE EXPECT A MAINLY QUIET WEATHER PERIOD LASTING
THROUGH THE DAYTIME HOURS TOMORROW. COLD FRONT AND MORE WIDESPREAD
CONVECTION, SOME STRONG, IS FORECAST FOR TOMORROW EVENING, LASTING
OVERNIGHT INTO MONDAY MORNING. CHAMBERS
PRELIMINARY POINT TEMP/POPS
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 058/086 061/081 054/076 050/081 054/086 057/081 053/075
00/B 73/T 00/N 00/B 00/U 11/B 32/W
LVM 048/084 051/073 041/072 041/080 047/083 049/079 045/074
00/U 74/T 20/N 00/U 00/U 13/W 43/T
HDN 053/089 058/084 050/078 045/083 048/088 052/083 049/077
00/U 43/T 00/N 00/U 00/U 01/B 32/W
MLS 062/091 065/085 054/076 049/081 051/087 055/082 051/076
01/B 33/T 30/N 00/U 00/U 01/U 32/W
4BQ 061/093 068/087 055/079 050/082 054/088 057/084 054/079
00/U 22/W 20/U 00/U 00/U 01/U 31/B
BHK 060/095 063/088 051/078 044/081 048/087 051/083 047/077
02/W 23/T 20/N 00/U 00/U 01/U 32/W
SHR 054/089 057/083 046/076 044/080 048/085 050/082 048/076
00/U 32/T 10/U 00/U 00/U 01/U 33/W
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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